OpenSC before 0.27.0, fixed in commit 0358817, contains a stack and heap buffer overrun vulnerability in the do_key_value() function in src/pkcs15init/profile.c that allows attackers to corrupt memory by supplying a crafted profile configuration file. During pkcs15-init invocation, a key value entry beginning with '=' followed by more than sizeof(keybuf) characters is copied into keybuf via memcpy without a length check, causing both stack and heap buffer overruns.
CVE-2026-40528
“—” beside the score: it is equal to NVD's CVSS score.
This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.2% (4th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 3.8 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-05-29) is not newer than that change (2026-07-21), so it does not.
- High severity, but no confirmed exploitation yet
An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.
- CVSS v3
- 7.8
- EG Score
- 7.8HIGHmedium confidence
- EG Risk
- 35EG Risk 35/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity78% × 45%Impact severity (EG Severity): CVSS 7.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.1% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release. - EPSS PROB
- 0.2%
- EPSS %ILE
- 4th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
May 29, 2026
Last Modified
July 21, 2026
Advisory Details (2)
Auto-updated Jun 10, 2026OpenSC < 0.27.0 Buffer Overrun in do_key_value() via profile.c | Advisories | VulnCheck
https://www.vulncheck.com/advisories/opensc-buffer-overrun-in-do-key-value-via-profile-ccommit 0358817ec74a (OpenSC/OpenSC)
Fix landed in OpenSC/OpenSC commit 0358817ec74a — awaiting tagged release
https://github.com/OpenSC/OpenSC/commit/0358817ec74aeca654f83e7709c7720b14c5db59Vendor Advisories for CVE-2026-40528(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 31× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 99 of 234 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 135 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-18 03:42 UTCEG score recompute
- 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-17 14:50 UTCEG score recompute
- 2026-10-17 14:50 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-12 16:09 UTCEG score recompute
- 2026-10-11 19:51 UTCEG score recompute
- 2026-10-11 17:05 UTCEG score recompute
- 2026-10-11 14:31 UTCEG score recompute
- 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 4th percentile
- 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-10-03 14:48 UTCOSV refresh
- 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
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- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
- 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-14 06:27 UTCEG score recompute
- 2026-09-14 06:27 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-13 02:09 UTCOSV refresh
- 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-25 04:27 UTCEG score recompute
- 2026-08-25 04:27 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-23 14:16 UTCEG score recompute
- 2026-08-23 14:16 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-21 15:12 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-20 23:38 UTCEG score recompute
- 2026-08-20 23:38 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-20 10:28 UTCEG score recompute
- 2026-08-20 10:28 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-17 06:54 UTCEG score recompute
- 2026-08-17 06:54 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-16 07:38 UTCEG score recompute
- 2026-08-16 07:38 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-15 19:20 UTCEG score recompute
- 2026-08-15 19:20 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-15 01:12 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-14 12:54 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-14 00:36 UTCEG score recompute
- 2026-08-14 00:36 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-13 02:15 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-12 13:57 UTCEG score recompute
- 2026-08-12 13:57 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-12 01:39 UTCEG score recompute
- 2026-08-12 01:39 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-11 13:21 UTCEG score recompute
- 2026-08-11 13:21 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.1% · 4th percentile
- 2026-08-10 23:58 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-10 11:29 UTCGHSA enrichmentGHSA-vxjj-52h8-95w5 · GitHub severity LOW · GitHub CVSS 3.8
- 2026-08-09 23:11 UTCEG score recompute
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Frequently asked(5)
What is CVE-2026-40528?
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What is the CVSS score of CVE-2026-40528?
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Dependency Blast Radius
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